Combined tank liner interphase barrier for oil circuit breakers



g- 3, 1967 R. MCCLOUD 3,335,245

J. COMBINED TANK LINER INTERPHASE BARRIER FOR OIL CIRCUIT BREAKERSOriginal Filed Nov. 5, 1960 9 Sheets-Sheet l INVENTOR. /6 /1461 ,2 61000Aug. 8, 1967 J R MCCLOUD 3,335,245

COMBINED TANK LINER INTERPHASE BARRIER FOR OIL CIRCUIT BREAKERS OriginalFiled Nov. 5, 1960 9 Sheets-Sheet 2 INVENTOR. wwvar ,9 M (2000 Aug. 8,1967 J. R; M CLOUD 3,335,245 COMBINED TANK LINER INTERPHASE BARRIER FOROIL CIRCUIT BREAKERS Original Filed Nov. 3. 1960 9 Sheets-Sheet 4 8,1967 J. R. MCCLOUD 3,335,245

COMBINED TANK LINER INTERPHASE BARRIER F'OR OIL CIRCUIT BREAKERSOriginal Filed Nov. 5. 1960 9 Sheets-Sheet MO/54 /76 M6 INVENTOR. ElJi/WQ' m aauo :f

g 1967 J. R. M CLOUD COMBINED TANK LINER INTERPHASE BARRIER FOR OIL 1960CIRCUIT BREAKERS Original Filed Nov. 3. 9 Sheets-Sheet 5 INVENTOR.JAM/5w A7Q000 g- 8, 1967 J. R. M CLOUD 3,335,245

COMBINED TANK LINER INTERPHASE BARRIER FOR OIL 1960 CIRCUIT BREAKERS 9Sheets-Sheet Original Filed Nov. 3.

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COMBINED TANK LINER INTERPHASE BARRIER FOR OIL CIRCUIT BREAKERS OriginalFiled Nov. 3. 1960 9 Sheets-Sheet Aug. 8, 1967 R. MCCLOUD 3,335,245

J. COMBINED TANK LINER INTERPHASE BARRIER F Original Filed Nov. 5. 1960OR OIL CIRCUIT BREAKERS 9 Sheets-Sheet United States Patent 1 Claim.(Cl. 200-150) This invention relates to oil circuit breakers, and morespecifically relates to a three-phase oil circuit breaker which isenclosed in a single tank. This application is a division of copendingapplication Ser. No. 396,796, filed Sept. 4, 1964, now abandoned andwhich was, in turn, a divisional application of application Ser. No.67,125, filed Nov. 3, 1960, now abandoned.

Oil circuit breakers of the type to which my invention is directed, andfor illustrative purposes may be rated at 34.5 kilovolts at 1500 millionvolt amperes, normally have a single phase contained in a respective oiltank whereby the contacts are separated in oil for permitting effectiveare interruption.

In the present invention, a multiphase circuit breaker unit has each ofthe phases contained in a common tank, this being made possible by thecombination of many novel features in the construction of the variousconstituent elements of the circuit breaker.

In accordance with one feature of the invention, I provide an exhaustvent means in the upper dome of the tank which serves the purpose of thewell-known breather pipes of the prior art. In the past, however, thesevents have had an internal bame structure for preventing the entrance offoreign matter from areas external to the tank, such as oil spray andthe like. I have improved this baflie construction, and form thebreather pipe to have two filters of a filter bronze at either end tocondense vapor oil and keep oil from escaping and to relieve gaspressure, and further form the pipe to have a re-entrant bend whichprevents the entrance of rain or high pressure water used in washingdown the equipment into the tank.

As a further feature of the invention and since the operating linkage iscontained external of the tank structure, it is necessary to introducesome type of link through the tank wall in order to transmit motion fromthe operating mechanism to the internally positioned contact operatinglinkage. It is necessary that the entrance of this rod will not permitan opening through which oil or gas Within the tank can escape into theoperating mechanism housing, particularly during interruptingconditions.

Accordingly, I have provided a novel seal which effectively seals theinterior of the tank from the interior of the operating mechanismhousing, even though the rod which must interconnect these two has bothan axial motion and a lateral motion This seal is more specificallyformed of a plurality of plates or thin sheets having a very closeclearance around the interconnecting rod. These thin sheets are thencontained within two adjacent plates which are relatively fixed, andhave relatively large apertures therein for passing the connecting rod.

The two plates are further arranged to compress the thin sheets intorelatively light mechanical engagement with respect to one anotherwhereby the sheets are capable of having lateral motion with respect tothe containing plates and with respect to one another, while stillproviding an effective seal between their internal diameter and theexternal diameter of the connecting rod carrying the sheets.Accordingly, an effective seal is formed, even though the connecting rodhas both axial and lateral motion with respect to the two plate memberswhich are stationarily positioned and carry the sheets.

3,335,245 Patented Aug. 8, 1967 Alternative to the use of flat disks,the seal may be formed of a single disk of flexible material such asneoprene which is biased toward a sealing disk by a biasing means whichwill not be defeated by low pressure conditions in the tank.

In order to prevent a line to ground fault by an expanding gas bubblefrom an interrupter hitting the side of the tank, it has been thepractice to place an insulating liner on the inner surface of the tankwall. There is the additional danger of a line to line fault when anexpanding gas bubble connects two interrupters in the tank, and it hasbeen the practice to provide insulating barriers between phases toprevent this condition. In accordance with the present invention, aunitary structure is provided for achieving both tank wall insulationand a phase to phase barrier. Thus, a single insulating strip will lieadjacent a first circumferential portion of the tank, and its ends arethen directed toward the center of the tank to form an insulated chamberfor one phase of the interrupters. A second insulating strip, formed inthe same manner, forms an insulated chamber for another phase of theinterrupters, and one of its ends is connected to an adjacent end of thefirst insulating strip. A third insulating strip forms a third chamberfor the third phase, and its two ends communicate with the free ends ofthe first two insulating strips whereby each of the phases is insulatedfrom one another and the interior of the tank wall is lined.

A novel manner is also provided for securing the cross bar which carriesthe movable bayonet type contacts to the lift rod which carries thecross bar. Generally, the lift 'rod is made of wood, and it is providedwith notches on either side which receive parallel connected andadjacently disposed metallic cross bars.

Considerable trouble has been experienced in the past since the notch inthe wood is subject to fracture along the grain of the wood andadditionally require relatively precise machining so that the dimensionof the notch exactly receives the cross bar dimension.

I have found that I can eliminate these problems by merely keying thecross bars with respect to the lift rod so that additional supportcorners are provided in the wood by providmg a plurality of keys, andthe requirement for an extremely accurately dimensioned notch in thewood is eliminated.

The concept of keying can be carried further to the securing of themetallic block member connected to the cross bars Where the metallicblock member carries the bayonet type contact. That is to say, in thepast, the metallic block member which receives the movable contact hashad a single notch cut in the opposing sides thereof which receive thecross bar members in the same manner that the cross bar members werereceived by the wooden lift rod.

In accordance with the present invention, however, the relativelycomplex machining of the metallic block member is avoided through theuse of a plurality of keying members which communicate between the crossbars and the block.

The necessity for adjustably mounting the interrupter chamber has beenset forth above where the interrupter chamber is adjustably mounted sothat it can be positioned in a lateral plane by means of the eccentricball connection. I have also found that the movable contact itself maybe adjustably secured to the mounting block which carries the movablecontact so that additional adjustment of the movable contact positionmay be achieved.

More specifically, the mounting block is modified to threada'bly receivea cylindrical mounting member in the form of a split ring. The splitring has an off-center threaded opening to receive the movable bayonettype contact whereby rotation of the ring will move the contact the liftrod can be formed of a Fiberglas rod which is superior to the previouslyused wooden rod.

One of the problems heretofore in using a Fiberglas rod was in thedifficulty of connecting the rod to the steel output linkages of theoperating mechanism and in guiding the motion of a circular rod.

In accordance with the present invention, a steel link is connected tothe end of the Fiberglas rod by using a Fiberglas hollow tube whichterminates in an outwardly flared internal taper of 2 with respect tothe axis of the tube. The connecting steel link has a cooperatinginwardly directed taper, and the two tapered surfaces are joined bygluing with an epoxy type of glue. By using this 2 taper, it has beenfound that a superior joint is formed with respect to a joint with notaper or with a relatively sharp taper.

In order to guide the round Fiberglas tube on the support, an annularguide member which may be of Bakelite is supported with respect to thetube as by supporting the Bakelite guide ring within a Fiberglas tubewhich is outwardly concentric with the Fiberglas rod and is secured byany fixed structure such as the lift frame mechanism.

The end of the Fiberglas tube is connected to the cross bars as bysecuring the tube to an aluminum block through the use of a wire ring onthe outer surfaces of the Fiberglas tube which cooperates with an innerannular cut in the block, and the aluminum block is then secured to thecross bars as by the keying method described above which positions thecross bars with respect to the block.

Accordingly, the primary object of this invention is to provide a novelmultiphase oil circuit breaker which may be enclosed in a single tank.

Another object of this invention is to provide a single tankconstruction for a multiphase oil circuit breaker having a rating of theorder of 34.5 kilovolts.

Another object of this invention is to form a single tank structure fora multiphase circuit interrupter wherein a removable upper dome sectioncompletely mounts the multiphase circuit breaker.

Another object of this invention is to provide a novel breather pipe foroil tanks which are to receive crcuit breakers which includes at leastone bronze filter memher, and has a re-entrant portion for preventingthe entrance of external foreign matter.

Another object of this invention is to provide a novel mounting meansfor an interrupter structure which is to be mounted to a terminalbushing within an oil tank wherein the interrupter structure isadjustably mounted in a vertical and lateral direction.

A still further object of this invention is to provide a novel unitarybarrier means for lining the interior of the tank and forming a barrierbetween phases to prevent line to ground faults and line to line faults.

A still further object of this invention is to provide a novel unitarybarrier means for lining the interior of the tank and forming a barrierbetween phases to prevent line to ground faults and line to line faults.

Another object of this invention is to provide a novel means forsecuring the cross bars to the lift rod.

Another object of this invention is to provide a novel manner forsecuring cross bars to a wooden lift rod through the use of a keyingstructure which eliminates the need for an enlarged notch in the woodencross bar.

A further object of this invention is to provide novel means forsecuring the contact block carrying a bayonet type contact to the crossbars.

Yet another object of this invention is to provide a keying type ofstructure for mounting the contact carrying block to the cross bars.

A further object of this invention is to provide a novel eccentric typeof adjustable connection between the movable contact and the cross barsto permit lateral adjustment of the movable contact with respect to thecross bars.

A further object of this invention is to provide a novel lift rodconstruction which includes a Fiberglas tube.

Yet another object of this invention is to provide a novel manner forconnecting a hollow Fiberglas tube to a solid steel member.

Another object of this invention is to glue a hollow Fiberglas tube to asteel rod by forming a 2 tapered joint with respect to the axis of therod.

Another object of this invention is to provide a novel guide means forguiding a round Fiberglas lift rod which includes an annular guidesupported within a supporting tube which is concentric with respect tothe rod.

Another object of this invention is to provide a novel gas seal betweena circuit breaker oil tank and an operating mechanism whereby a linkextending between the two may have axial, angular, and lateral motionwithout defeating the seal.

A further object of this invention is to provide a novel gas sealbetween two containers which have a common member extending therebetweenwhich includes a plurality of thin plates enclosing the common memberand movable between the two stationary enclosing supports.

These and other objects of this invention will become apparent from thefollowing description when taken in connection with the drawings, inwhich:

FIGURE 1 shows a top plan view of my novel multiphase oil circuitbreaker which is contained in a single tank.

FIGURE 2 is a side plan view of FIGURE 1.

FIGURE 3 is a front plan view of FIGURE 1.

FIGURE 4 is a side cross-sectional view of the tank of FIGURE 1 whentaken across the lines 4-4 in FIG- URE 1, and lines 44 in FIGURE 3.

FIGURE 5 is a side view of the tank of FIGURE 3 with a portion of thetank wall removed and with two interrupters removed.

FIGURE 6 is a side cross-sectional view of the exhaust structure in theupper tank portions of FIGURES 4 and 5.

FIGURE 7 is a side cross-sectional view of the gas seal formed betweenthe tank housin and operating mechanism housing of FIGURE 4.

FIGURE 8 is a detailed cross-sectional view which illustrates the mannerin which the upper dome portion of the tank is connected to the lowerdome portion of the tank.

FIGURE 9 is a partially cross-sectional view of one of the interruptingchambers of FIGURES 4 or 5, and particularly illustrates the noveleccentric ball connection between the interrupter chamber and thebushing associated therewith.

FIGURE 10 is a cross-sectional view of the eccentric ball connection ofFIGURE 9 taken across lines 10-10 in FIGURE 9.

FIGURE 11 is a detailed side cross-sectional view which illustrates themanner in which the current tra'nsformer leads are taken through thetank Wall in a substantially gas tight manner.

FIGURE 12 shows an enlarged plan view of the operating linkage of FIGURE4 when the linkage is in the closed circuit position.

FIGURE 13 is similar to FIGURE 12 and shows the linkage positionimmediately prior to contact closure.

FIGURE 14 shows an enlarged cross-sectional view of the damping springof FIGURE 4 for limiting over-travel of the movable contact.

FIGURE 15 shows an enlarged section view of the manner in which the liftframe is adjustably secured to the upper dome section.

FIGURE 16 shows an alternative structure for the gas seal of FIGURE 7.

FIGURE 17 shows a top view of the tank interior and particularlyillustrates my novel barrier for serving as a tank liner and as abarrier between phases.

FIGURE 18 is a side cross-sectional view of FIG- URE 17.

FIGURE 19 shows the usual cross bars to a wooden lift rod.

FIGURE 20 is a side View of FIGURE 19.

FIGURE 21 illustrates the manner in which the fastening structure ofFIGURES l9 and 20 is modified in accordance with the invention.

FIGURE 22 is a side view of FIGURE 21.

FIGURE 23 is a cross-sectional view which illustrates the presently usedmanner in which the movable bayonet type contact is secured to the crossbars.

FIGURE 24 is 'a side cross-sectional view similar to FIGURE 23 whichillustrates the modification in securing the 'movable contact to thecross bars in accordance with the present invention.

FIGURE 25 is a top view of FIGURE 24.

FIGURE 26 is a side cross-sectional view of a modification of theembodiment of FIGURE 24 whereby the movable contact is laterallyadjustable.

FIGURE 27 is a top view of FIGURE 26.

FIGURE 28 is a side partially cross-section view of a Fiberglas lift rodand illustrates the manner in which the lift rod is secured to the crossbars and to the upper operating linkage, as well as the manner in whichthe lift rod is guided.

General arrangement manner of fastening the The general arrangement ofthe circuit breaker exterior including its support is shown in FIGURESl, 2 and 3.

Referring now to FIGURES l, 2 and 3, the assembled circuit breaker andtank 20 is supported by four legs 22, 24, 26 and 28 which are formed ofelongated angles. Legs 22, 24, 26 and 28 are braced to prevent movementwith respect to one another by bracing members,'such as braces 30 and 32of FIGURE 3, and braces 34 and 36 of FIGURE 2. The legs are then securedto base angles 38 and 40 by anchor bolts or the like which extendthrough the base angles, as is shown in FIGURE 3 for the case of bolts42 and 44.

A geared tank lifter 46 is provided, as seen in FIG- URE 2, for raisingor lowering oil tank 20 with respect to legs 22 through 28 in the usualmanner.

An operating mechanism housing 48 is positioned externally of thecircuit breaker tank 20 and is also carried by legs 26 and 28 in anydesired manner. The mechanism internal of housing 48 may be of anystandard type and will not be described in detail in the presentapplication. It is sufiicient for purposes of the present invention tounderstand that the mechanism housing 48 will contain an operatingmechanism which will cause the motion of internal linkages to betransmitted to the operating linkage to be described more fullyhereinafter in connection with FIGURE 4, and also that the operatingmechanism may be energized automatically responsive to signals derivedfrom current transformers contained within tank 20 and brought into theoperating mechanism through conduit pipes 50.

As best seen in FIGURE 1, a plurality of terminal bushings 52, 54, 56,58, 60 and 62 respectively are carried by the upper portion of tank 20in a manner to be described more fully hereinafter. These bushings arecircumferentially arranged with respect to the top of tank 20, and arearranged on the surface of a cone, which cone converges inwardly towardthe bottom of tank 20.

The manner in which these terminal bushings are mounted with respect totank 20 whereby the complete circuit interrupter is mounted to aremovable portion of the tank 20 will be seen more fully hereinafter.

Tank structure The general tank arrangement of tank 20 is bestunderstood by reference to FIGURES 4 and 5. In the figures, it will beseen that the tank has an enlarged upper head portion. Morespecifically, the tank is formed of a lower cylindrical portion 64 andan upper dome portion formed of hemispherically-shaped casings 66 and68. If desired, hemispherical casings 66 and 68 may be of identicalcross-section, although in the embodiment presented herein, casing 68has a larger diameter than does casing 66. The central portion of lowercasing 66 is cut-out, and the cut-out portion may be used as the bottomwall 70 of the tank. Thus, a substantial economy of tank constructionmay be effected.

The two hemispherical sections 66 and 68 are joined in a manner bestshown in FIGURES 5 and 8 by securing a ring 72 to lower hemisphere 66 asby welding and by securing a notched ring 74 to upper hemisphere 68.Ring 74 has a notch 76 therein which carries a suitable gasket material,such as cork or any other desired material filler, and receives theupper end of ring 72.

A plurality of mounting blocks, such as blocks 78 and 80 of hemisphere66 shown in FIGURE 5, and block 82 of hemisphere 68 may then be boltedtogether by cooperating nuts and bolts, such as nut 84 and bolt 86,whereby the upper portion of ring 76 of FIGURES 5 and 8 will be drivendeeply into the filler within groove 76 of ring 74. Accordingly, theupper and lower hemispheres 68 and 66 respectively will be firmlyconnected with respect to one another in a substantally gas tightmanner.

The consequences of providing an enlarged head or enlarged upper portionfor the tank will be described more fully hereinafter as permitting theentrance of a plurality of bushings having current transformersassociated therewith, so that a multiphase interrupter can be associatedwith the single tank 20, while, at the same time, only a small oilvolume is necessary.

In each of FIGURES 4 and 5, it will be understood that the tank is to befilled with oil which will act as an arc quenching material for the arcinterrupters to be immersed in the tank. The oil level within the tankis best shown in FIGURE 5 by the dot-dash line labeled oil level, and itwill be seen that the major portion volume is contained within lowercylindrical portion 64 of the tank which defines a relatively smallvolume.

As best seen in FIGURE 5, the oil tank portion 64 further has a tankliner 88 of insulating material which prevents gases expelled from thearc quenchers or interrupters contained within the tank fromestablishing a current carrying path to the tank wall, and, thus, causea short circuit to ground.

The bottom wall 70 of tank 20 has an extending cylindrical casing 90welded thereto to serve as a seat for the tank, and also protects thedrain valve 92 from damage.

The upper hemisphere 68 of tank 20, as shown in FIG- URE 5, has anexhaust structure or breather pipe 94 associated therewith whichcommunicates between the air above the oil level Within the circuitbreaker tank and the external atmosphere. The main purpose of breatherpipe 94 is to vent gases generated during arc extinction. It is,however, imporant that no foreign matter be brought from the externalatmosphere into the tank, such as rain or water from high pressurecleaning hoses, and in a like manner, it is important that oil from thetank is not vented through breather pipe 94.

Accordingly, I construct the breather pipe of a conduit 96 which has afirst elbow 98 secured thereto as by welding. A second elbow 100 is thenconnected to elbow 98 so as to form a re-entrant member.

A first and second bronze fiber filter 102 and 104 respectively are thenpositioned within conduit 96, and are spaced from one another by atubular spacer 106. Clips, such as clip 108, and a ring, such as ring110, then hold all of the parts in position with respect to one another.

The pipe elbows 98 and 100 will direct the gas flow during arcinterruption back toward casing 20, rather than outwardly and towardoperating personnel. At the same time, the re-entrant shape of thebreather pipe will prevent rain from entering the breaker, while theadded return bend created by elbow 100 aids in preventing high pressurewater used in washing down the equipment from entering the breaker.

Mounting of circuit breaker equipment with respect to the bar Aspreviously described in FIGURES l, 2 and 3, bushings 52 through 62 arecarried with respect to tank 20-. The manner in which these bushings areconnected to the tank is best shown in FIGURES 4 and which show thecircuit breaker being carried from removable dome section 68.

Referring particularly to FIGURE 5, particularly to the mounting ofbushing 52, the upper dome 68 is bumped to provide a flattened portionwhich is then provided with an enlarged aperture for receiving the lowerextending portion 112 of bushing 52. In a like manner, dome 68 hasopenings in other bumped portions for each of the other extendingbushing portions for bushings 54 through 64. By flattening theseportions of the tank, inserts are not needed to compensate for the domecurvature. Each of the bushings is provided with a flange collar, suchas flange 114 'for bushing 52, and similar flanges 116 and 118 forbushings 60 and 58, respectively, of FIGURE 5.

The lower portion of the flanges, such as flange 114, is seated upon aball joint flange, such as ball joint flange 120 for bushing 52 whichincludes members 119 and 121 which are seated on at least three studs127 (only two of which are shown) welded to the flattened portions oftop head 68. Members 119 and 121 engage one another along an annularconical surface so that member 121 can be skewed as desired, and theposition of member 121 and thus flange 114 will be fixed in any desiredposition by tightening bolts 128 of studs 127. A gasket such as gasket126 then seals the connection so it will be gas tight. Similar balljoint flanges 122 and 124 are provided for bushings 60 and 58respectively.

In a like manner, each of bushings 54 through 6-2 will be directlysecured to top head 68 as by ball joint members 122 and 124 for bushings60 and 58 respectively. Accordingly, the bushings are directly carriedby the top head 68 and can be lifted as a unit with respect to the mainbody of the tank.

Interrupter structure and mounting of the interrupter structure Each ofbushings 52 through 62 of the figures are terminated with an interrupterwhich essentially comprises a housing containing a relatively stationarycontact element which is adapted to receive a relatively movable contactwhereby a cross blast of oil will be passed through the contacts whenthey are moved to their disengaged position to help in extinguishing anarc drawn thereby.

Typical interrupter structures which may be used in the structuredescribed herein are set forth in copending applications Ser. Nos. 2,390and 2,530, respectively.

The interrupter structures for each bushing are shown in FIGURES 4 and 5as interrupters 130, 132, 134, 136 and 138 for bushings 52, 54, 56, 58and 62, respectively.

8 A similar interrupter structure is provided =for bushing 60 which isnot shown in FIGURES 4 and 5 for purposes of clarity.

Interrupter structure which is typical of all of the interrupters of theunit is shown in an enlarged partial cross-sectional view of FIGURE 9.Referring to FIGURE 9, the interrupter or are quencher 130 is comprisedof a conductive contact support member 140 which is electricallyconnected to a plurality of circumferentially arranged stationarycontact fingers, such as contact finger 142, and one elongated arcingcontact finger 144. The manner in which these contact fingers areconnected to contact support 140 is described in detail in either of theabove noted copending applications, Ser. No. 2,390 or Ser. No. 2,530.

A housing or container 146 which may be of Fiberglas is then connectedto contact support 140 through a casting member 147, and carried aplurality of baflles and arc splitters in the manner shown in the abovenoted copending applications which communicate with vents (not shown) inchamber 146. The are splitters and baffles within chamber 146 have anaxial opening therein which receives a bayonet-type movable contact 148in FIGURE 9 for interrupter 130. In a like manner, all of the other areinterrupters associated with the other bushings of FIG- URES 4 and 5have a similar bayonet-type movable contact entering therein andcooperating with the tuliptype cluster of stationary cont-acts connectedto their respective contact support. Thus, when the movable contacts,such as contact 148 which is shown in the engaged position in FIGURES 4,5 and 9, are withdrawn down wardly to a disengaged position, an arc willbe drawn between arcing contact 144 and 148 so as to generate arelatively high pressure due to dissociated oil which, in turn, willdrive oil between the disengaging contacts and outwardly of the vents inchamber 146 to extinguish the arc.

Each of the interrupters are mounted to their respective bushings in anovel manner which permits vertical, lateral and plumb adjustment of theinterrupters. This feature is necessary since proper clearance andalignment must be kept between the various interrupter structures, andbetween each of the interrupters and their respective bayonet-typemovable contact.

The manner in which the electrical and mechanical connection is madebetween the bushing studs and the interrupters is best illustrated inFIGURES 9 and 10 for the case of interrupter 130 and bushing 52, and iscomprised of an eccentric-type ball socket arrangement. The contactsupport 140 is provided with a central opening 150 having a taperedsurface 152 at the top thereof. An eccentric ball 154 of conductivematerial has a lower surface which may be tapered at an angle whichcooperates with taper 152, as shown, or may be of a partially sphericalexternal surface which will engage surface 152.

The internal diameter of ball 154 is threaded by threads 158 whichcooperate with an external thread on bushing stud 160 of bushing 52 sothat the ball 154 may be threaded on lbushing stud 160. A split lockring 162 of conductive material which is split by virtue of slot 164(FIGURE 10) has an upper internal taper 166 which falls on the uppersurface of ball 154 which may be either plane or circular, as is thecase for the lower surface of the ball, and the lock ring 162 furtherhas a lower internal thread 168 which cooperates with an external threadon contact support 140.

The split lock ring 162 is then provided with "a clamping means whichcomprises, as best seen in FIGURE 10, a first and second lug 170 and 172respectively wherein a bolt 174 passes through a clearance opening 176(FIG- URE 9) in lug 172 and then into a cooperating internal thread inlug 170. Accordingly, by tightening screw 174 into lug 170, the splitlock ring 162 will be contracted. A similar upper screw clamp meanswhich includes clearance opening 178 in the upper lug of FIGURE 9 isalso provided whereby the split lock ring is clamped by the two screwmembers.

In operation, this structure will permit both vertical, lateral andplumb adjustment of interrupter structure 130 with respect to bushing52. More specifically, when assembling the joint the split lock ring 162is laid on top of eccentric ball 154, and the eccentric ball 154 is thenthreaded on to bushing stud 160. Locking ring 162 is then rotatedindependently of eccentric ball 154 onto the external threads of contactsupport 140 until the interrupter 130 assumes an appropriate Verticalposition.

Lateral adjustment of interrupter 130 is achieved by appropriatelyangularly positioning ball 154 with respect to stud 160, wherebyrotation of eccentric ball 154 will cause a lateral motion ofinterrupter 130 with respect to bushing 52.

Finally, the correct plumb of interrupter 130 is achieved byappropriately angularly positioning interrupter 130 by causing thetapered surfaces 152 of contact support 140 and tapered surface 166 oflock ring 162 to rotate with respect to eccentric ba'll 154.

Once the appropriate position is assumed, the lock screws, such as lockscrew 174, are firmly tightened to cause a contraction of lock ring 162and a like contraction of split eccentric ball 154 whereby the threadsjoining ball 154 and bushing stud 160 are firmly connected, and thethreads joining locking ring 162 to contact support 140 are also firmlytight. Accordingly, a rigid mechanical connection is formed betweenbushing 52 and interrupter 130, and at the same time, a low resistanceelectrical connection is formed from stud 160 onto contact support 140.

Mounting of current transformers As previously indicated, each ofbushings 52 through 62 have current transformers associated therewithwhich may be used to initiate operation of the operating mechanismresponsive to predetermined current conditions in any of the phases.These current transformers may be internally mounted of the tank byvirtue of the enlarged dome section, and are shown in FIGURE ascomprising current transformers 180, 182 and 184 for bushings 52, 54 and56, respectively. In a like manner, Ibushings 58, 60 and 62 will havesimilar current transformers associated therewith.

The current transformers are constructed in the standard manner, andinclude two magnetic cores 186 and 188 for the case of currenttransformer 180, which each have a secondary winding associatedtherewith. The central bushing conductor serves as the primary windingfor the current transformers.

In mounting current transformer 180, a first insulating spacer 190 isplaced between the upper surface of the winding of core 186 and theupper tank surface, while a second insulating spacer 192 is connectedbetween the two .transformer elements, and a third insulating spacer 194is placed between the lower transformer 188 and a bottom support plate196. The bottom support plate has openings therein for receiving aconnecting rod, such as rod 198, which is connected to the top of thetank and is fastened to the lower plate 196 by bolts, such as bolt means200.

Each of the other current transformers are mounted in the same mannerabove described for current transformer 180. Thus, for example, currenttransformer 182 is mounted by means of rod 202 which has one endconnected to the tank top and a lower end connected to 'lower plate 204.

It is now necessary to bring out the leads from the current transformersecondary windings to the operating mechanism through conduit 50, asabove described in connection with FIGURE 2. In order, however, to bringthe leads out of the tank, it is necessary to continue to retain theseal between the tank and external atmosphere for oil, gas and exteriormoisture. I have found a novel method for bringing these leads out ofthe tank through opening 206 shown in FIGURE 4 in the upper dome 68,while still sealing opening 206 against the external atmospherc. Thisseal is best shown in FIGURE 11 which fragmentarily shows opening 206 inthe wall of upper dome 68 in cross-section, and also shows leads 208 and210 which are to be taken out through opening 206. If desired, thecurrent transformer secondaries may be connected internally of the tankand the two common leads 208 and 210 then taken out; or, if desired,insulated leads from each of the current transformers may be taken outso that information as to which phase delivered a fault signal could beobtained at a remote point.

In order to accomplish this, and still retain a gas tight seal, Iprovide a first exit tube 212 which is welded to opening 206 and has abolt plate 214 connected to the outer end thereof. A second exit tube216 is then provided with a second bolt plate 218 welded to one endthereof. The bolt plates 214 and 218 are so arranged as to provideopposing shoulders which receive insulating plates 220 and 222respectively which have a rubber plate 224 or a plate of similarflexible material therein. Each of plates 220, 222 and 224 haverelatively small centrally disposed openings therein for receiving leads208 and 210.

The bolt plates 214 and 216 then have a plurality of interconnectingbolts, such as bolt 226, which operate to draw the plates toward oneanother when the bolts are tightened. Therefore, after the unit isassembled, as shown in FIGURE 11, and tightened, the rubber plate 224will be compressed and forced to flow around leads 208 and 210 andagainst the junction of plates 214 and 218 to thereby completely sealopening 206.

Current path Referring to FIGURES 4 and 5, it has been previouslydescribed that each of the interrupter structures or are quenchers, suchas arc quencher 138, cooperate with rnovable bayonet-type contacts, suchas movable contact 148 of FIGURE 9. When the unit is adapted forthree-phase operation, two interrupters are connected in series for eachphase. For example in FIGURE 5, a first phase will include bushings 52and 58. Interrupters and 134 of bushings 52 and 58 respectively areconnected in series by virtue of conductive cross bars 228 and 230 whichelectrically connect movable contact 148 which cooperates withinterrupter 130 to movable contact 232 (FIGURE 5) which cooperates withinterrupter 134.

The second phase includes the series connection of interrupter 132associated with bushing 54 and interrupter 136 associated with bushing56 by virtue of cross bars 234 and 236 which electrically connect themovable bayonet-type contacts of the interrupters associated withbushings 54 and 56.

Finally, the last phase is completed by the series connection of themovable contact associated with interrupter 138 associated with bushing62 and the interrupter associated with bushing 60 by virtue of crossbars 238 and 240 which electrically connect the movable contactsassociated with these interrupters. The cross bars 228230, 234-236, and238-240 are constructed in the standard manner of previous single crossbars used in a single tank, but are supported in a novel manner to bedescribed hereinafter.

From the foregoing, it will be clear that the electrical path throughany one phase, such as the phase including bushing 52, will be from theexternal connector of bushing 52, the internal bushing conductor,bushing stud 160, ball 154, contact support 140, the tulip-type clusterof stationary contacts such as contact 142 of FIGURE 9, the movablebayonet contact 148, cross bars 228 and 230, the movable bayonet contact232 of interrupter 134, the stationary tulip-type cluster of stationarycontacts of interrupter 134 and thence out through the central bushingconductor of bushing 58 to the external connector for bushing 58.

The cross bars previously discussed and shown in FIG- URE 4 for eachphase are carried by insulating lift rods which may be of wood. Thus,cross bars 228 and 230 are clamped in any desired manner to verticallift rod 242.

In a like manner, cross bars 234 and 236 are connected to a wooden liftrod 244, while cross bars 238 and 240 are connected to wooden lift rod246. The lift rods 242, 244 and 246 are vertically movable so as to movetheir respective cross bars and the movable contacts connected to thecross bars downwardly toward a disengaged position with respect to thestationary tulip cluster contacts of the interrupting structures andupwardly to the engaged position shown in the figures. Note that inFIGURE 5 the disengaged position of the cross bars is shown in dot-dashlines.

The manner in which the cross bars 242, 244 and 246 are connected to theoperating mechanism will be described more fully hereinafter.

Since the lift rods are relatively long, a guide means for guiding theirmotion is provided by insulating guide board assemblies of an identicalnature. These guides are securely bolted to the lift mechanism frame 248of FIG- URE 4 which includes angles 248a and 248b of FIG- URE 5. Thelift frame 248 permits the lifting of the complete circuit interrupterby lifting the upper dome 68 with respect to lower dome 66, and includeswooden support members 250, 252 and 254 for cross bars 242, 244 and 246,respectively. The lift frame can be adjusted both vertically andhorizontally with respect to the ring 74 by securing an angle 249(FIGURE 4) to ring 74 and securing a flange 251 of frame 248 as shown inFIGURE 15 to angle 249 by hollow bolts 253a and 253b which threadthrough tapped openings in angle 249. The bolts 253a and 253b are thenadjusted until frame 248 is appropriately positioned, and securing bolts255a and 255b are then passed through bolts 253a and 253b and aresecured. As is best seen in FIGURE 5, the support members, such assupport member 254, are formed of two parallel elements 254a and 2541;.Each of the members 250 through 254 is terminated with protruding guidemembers, best seen in FIGURES 4 and 5 for the case of lift rod 246 asguide members 256 and 258 carried by elements 254a and 25%,respectively. A similar pair of guide members is provided for lift rods242 and 244, one

of which is seen for each of these lift rods as guide members 260 and262, respectively.

A pair of rollers are then carried by the adjacently positioned guidemembers, such as rollers 264 and 266 of guide members 256 and 258 whichstraddle the lift rod 246, While similar rollers are provided for theguide members of lift rods 242 and 244. Accordingly, as the lift rodswhich are connected to the operating linkage at their upper ends arevertically moved, they will be guided by virtue of the straddlingrollers described above, and will retain proper alignment and rigidity.

Operating linkage The operating linkage for transmitted force fromoperating mechanism 48 to the lift rods 242, 244 and 246 is best seen inFIGURES 4, 12 and 13, where FIGURE 4 shows the operating linkage foreach of the phases, while FIGURE 12 shows the operating linkage asextending only to lift rod 246 with the contacts in the closed position,while FIGURE 13 shows the linkage for lift rod 246 for the position ofthe contacts when they are just about to touch.

The operating mechanism 48 has an output link 270 which is operated inany desired manner by operating mechanism 48, such as by manual crankoperating means or by automatic means which are responsive to signalsderived from the current transformers, such as current transformer 180or by other electrical signals. Mechanism 48 may be of any standardtype, and it is only necessary for purposes of the present invention tounderstand that it operates the output link 2'70 upwardly to open thecircuit breaker and downwardly to close the circuit breaker.

The upper end of link 270 is pivotally connected to crank 272 at pin274. Crank 272 is pivotally mounted at relatively stationary pivot 276,and has an output link 278 pivotally mounted thereto at pin 280.

The right-hand end of link 278 is pivotally connected to connecting rod282 and guide link 284 at pin 286, the guide link 284 being pivotallymounted to stationary pivot 288 in serving merely to guide the motion ofpin 286. The right-hand end of connecting rod 282 passes through a seal290 which will be described more fully hereinafter, and serves toisolate interior of tank 20 from the interior of operating mechanism 48,and is pivotally connected to bell crank 292 by pin 294. Bell crank 292is pivotally mounted to stationary pivot 296, and has its right-hand endpivotally connected to rocker arm 298 by pin 300. The upper end ofrocker arm 298 is pivotally connected to link 302 at pin 304, and thelower end of link 302 is pivotally connected to lift rod 246 by pin 306.

Pin 300 also pivotallyv connects bell crank 292 and rocker arm 298 tolink 308 which has its right-hand end connected to a plunger 310 whichextends through compression spring 312 and terminates on pressure plate314 of spring 312. When plunger 310 is moved to the left, it compressesspring 312 against spring seat 316, which is fastened to, or may be anintegral part of, the spring container 318. The spring container 318 iselongated, as shown, to permit full expansion of spring 312 when plunger310 moves to the right.

The lower end of rocker arm 298 is terminated with a roller 320 whichmoves in a guide slot 322 which is cut in the frame 248 whereby themotion ofpin 304 is fixed by virtue of the fixed pivot 296 for bellcrank 292 and the guided motion of roller 320 of rocker arm 298.

The lift rods 242 and 244 for the other phases of the circuit breakerare connected to rocker arms 324 and 326 in a manner identical to thatdescribed for rocker arm 298. Similarly, rocker arms 324 and 326 arepivotally connected to link 306, and have rollers at the bottoms thereofwhich are guided in slots 328 and 330, respectively. Therefore, themotion of lift rods 242, 244 and 246 will be identical because of thecommon connecting rod 308 which drives all of these elements in anidentical manner.

In operation, the spring 312 operates to bias the contacts to an openposition. Thus, the spring will move the lift rods 242, 244 and 246downwardly, and to a disengaged position when operating link 270 ofoperating mechanism 48 is released by a latch mechanism within theoperating mechanism (not shown) so that link 270 can move upwardly.

Assuming that the circuit breaker is in the disengaged position, inorder to close the circuit breaker, link 270 is moved downwardly tothereby rotate bell crank 272 about pivot 276 and thus move link 278 tothe left. This will cause link 282 to move to the left and rotate bellcrank 292 in a counterclockwise direction about pivot 296.

The rotation of bellcrank 292 will operate to move rod 308 to the left,and thus compress spring 312. At the same time rocker arms 298, 324 and326 move upwardly, it being noted that in the disengaged position rockerarms 298, 324 and 326 have their lower ends in the right-hand end ofslots 322, 328 and 330 respectively. Because of this upward motion, theupper ends of rocker arms, such as pin 304 of rocker arms 298, is drawnupwardly so that the lift rods, such as lift rod 246, will be movedupwardly and toward the engaged position.

The motion of pin 304 and the upper pins of rocker arms 324 and 326 willbe a vertical straight line motion in view of the relationship betweenfixed pivot 296 and slot 322. Accordingly, the mechanism operates toconvert the horizontal motion of connecting rod 282 to a vertical motionfor the lift rods, such as lift rod 246.

When the contacts reach their fully engaged position, a latch meanswithin the operating mechanism (not shown) engages and holds themechanism in position against the opening force of spring 312. When,upon demand, the operating mechanism is released or tripped, spring 312is no longer restrained, and it rapidly rotates bell crank 292 in aclockwise direction about its pivot 296 to cause rocker arms 298, 324and 326 to move rapidly downward in a straight line motion, aspreviously described, until the fully disengaged position is achieved.

As has been described, the operating linkage previously used in the artis such that an ever increasing mechanical advantage is applied to thelinkage during the closing stroke to assist the operating mechanism inclosing the the breaker at the end of the closing stroke. I haverecognized that the greatest need for mechanical advantage in theoperating linkage is immediately prior to the time that the circuitbreaker contacts touch during closing, at which time a pre-arc occursand creates forces tending to open the circuit breaker.

In the prior art linkages, where the mechanical advantage is everincreasing, it will be apparent that the maximum mechanical advantage isnot yet reached at this point, and is reached only when the linkageassumes the fully closed position. I have further recognized that whenthe contacts are in the fully closed position, the load on the operatingmechanism should be high to insure proper tripping by causing themechanical advantage in the operating linkage at that time to berelatively low.

In the linkage shown in FIGURE 4 and reproduced in FIGURES 12 and 13, itwill be seen that I have overcome the above two disadvantages, andprovide a mechanical advantage immediately prior to closing, which isextremely high in the linkage (FIGURE 13), while the mechanicaladvantage under the fully closed condition of FIGURE 12 is relativelylow. That is to say, when the circuit breaker is in the closed positionof FIGURE 12, the effective lever arms 332 and 334 yield a relativelylow mechanical advantage for transmitting force between link 270 andconnecting rod 282. When, however, the linkage is moved to the positionimmediately prior to contact touch, the effective lever arm 336(corresponding to previously effective lever arm 332) is greater thaneffective lever arm 332, while the effective lever arm 338 whichcorresponds to previous lever arm 334 remains relatively constant.Accordingly, the mechanical advantage immediately preceding contacttouch is relatively high, while the mechanical advantage in thecompletely closed condition is relatively low by virtue of theinterconnection and relative positions of bell crank 272 and link 278which drives connecting rod 282.

A second spring is provided over each of the lift rod connecting links,such as link 382 for lift rod 246, such as compression spring 340, forthe purpose of limiting over-travel of the lift rods at the end of theclosing stroke. More specifically, and as best shown in FIGURE 14,spring 340 bears on a plunger 342 of FIGURE 4 which is movable within aspring containing cylinder 344 and engages the top of link 302. Themotion of plunger 342 is limited by virtue of its containing cylinder344, so that after a relatively short travel of plunger 342, when pushrod 246 is moved downwardly, the lower end of plunger 342 will leave rod302. Accordingly, the spring 340 serves to deliver an extremely highforce for a short period of time during the initial operation of thelift rods to a disengaged position, and at a point where rapidacceleration is extremely desirable. If desired, the spring force may beadjusted by virtue of an adjusting nut 346 which adjusts the compressionof the spring 340 in its fully extended position.

The unit is sealed from outside moisture by means of any desired type ofcap which is bolted to cylinder 344 and the O-rings 350 and 352. Asshown in FIGURE 14, the plunger 342 and cap 348 have aligned centralopenings 353 and 355. An analyzer rod 357 may, as shown in FIGURE 14,pass through openings 353 and 355 and be connected to the upper portionof link 302 whereby the analyzer rod will move with lift rod 246.Accordingly, the analyzer rod may serve to graphically record the exactmotion of the movable contacts, whereby information may be obtained asto the rate of contact opening, rate of contact closing, contact bounce,etc.

Seal between tank and operating mechanism As previously described, it isnecessary to seal the passage which communicates between tank 20 andoperating mechanism 48 and permits passage of connecting rod 282 betweenthese elements. The problem is aggravated, since connecting rod 282 notonly has a horizontal motion, but also has a slight lateral and angularmotion, so that a typical slide gasket cannot be used.

I have found a novel method of sealing these elements, even though amember having horizontal, angular and lateral motion must pass throughthe seal. The seal structure 290 of FIGURE 4 which achieves this end, isbest seen in the enlarged cross-sectional view of FIG- URE 7.

Referring now to FIGURE 7, a plate 354 (see FIG- URE 4) is secured inthe passage between tank 20 and operating mechanism 48, and has anenlarged opening 356 therein for receiving connecting rod 282. A secondplate 358 is bolted to plate 354, as shown, through an interposedannular spacing ring 360. Plate 358 has an opening 362 therein similarto opening 356 for passing connecting rod 282.

A plurality of thin sheets 364 are then secured about rod 282 with avery close clearance between the internal diameter of the opening insheets 364 and the external diameter of rod 282. These seals are thencontained between plates 354 and 358, and have an outer diameter, suchthat for the greatest lateral motion of connecting rod 282, the sheets364 will still be contained between these plates. Accordingly, the rod282 may move horizontally with respect to plates 356 and 358, sincethere is some clearance, and plates 356 and 358 are free to move up anddown in a vertical plane as the rod moves laterally.

When there is lateral motion of rod 278, the thin sheets will movewithin the confines of plates 354 and 358 so that the openings 356 and362 are still substantially sealed. When there is an angular motion ofrod 282, the angular motion will not tend to rotate the complete groupof plates 364, since these plates may move with respect to one anotherwhereby the stack of plates will cant instead of attempting to rotatewith rod 282. To minimize this problem, it is preferable that the centerof rotation of rod 282, as determined by the motion of pin 286 and pin294 of FIGURE 4, be as close as possible to the center of the stack ofsheets 364. Thus, the plates on either side of this point will move inopposite directions for a minimum distance to absorb the rocking motionof the connecting rod 282, and at the same time, maintain a highlyeffective seal to prevent gases generated by are extinction fromentering the mechanism housing 48.

As an alternative to the sealof FIGURE 7, and instead of using a stackof thin plates, a sealing plate 370 may be positioned adjacent plate orsheet 354 and receive rod 282 through an enlarged clearance hole. Aflexible disk 372 which may be of neoprene closely fits around rod 282and is placed adjacent plate 370 and is backed up by a spring washer374. The spring washer 374 will operate to hold the neoprene disk 372 inposition even under low pressure conditions within the tank.

Unitary tank liner and interphase barrier The novel unitary tank linerand interphase barrier for the tank wall is shown in FIGURES l7 and 18where only the barrier is shown with the tank wall 64 and theinterrupter assemblies such as interrupters through 138 shown in phantomview.

As was shown for the case of FIGURE 5, the usual practice is to apply acircular tank liner such as tank liner 88 of FIGURE to the interior ofthe oil tank whereby an expanding gas bubble from any of theinterrupters during interrupting conditions will not be able tocommunicate from the interrupter to the tank wall to establish a line toground fault. In addition to this, in many high voltage applications,additional barriers are positioned between interrupters of differentphases to prevent the possibility of a gas bubble communicating betweenadjacent interrupters to establish a line to line fault duringinterruption.

In accordance with the present invention, both a tank liner andinterphase barrier are provided through a novel unitary structure. Thus,in FIGURES 17 and 18, a first liner portion 380 of any insulatingmaterial such as pressboard covers roughly one-third of thecircumferential area of the tank. The ends of insulating sheet 380 arethen turned inwardly as ends 382 and 384 are turned inwardly to form achamber or pocket around interrupter 138 and its series connectedinterrupter 140.

In a similar manner, a second insulating strip 388 of a material such aspressboard has inwardly extending ends 390 and 392 where strip 388 formsa chamber or pocket around interrupter 134. The ends 382 and 390 ofstrips 380 and 388, respectively, are secured along their length in anydesired manner as through the use of insulating bolts, tying or gluing,to mention three possibilities.

A still further insulating strip 394 then forms a chamher for insulators132 and 136 in the same manner as disclosed for insulator 380, and thechain of insulating strips is completed by strip 396 which forms achamber for interrupter 130.

In view of the configuration presented, it is seen that each adjacentinterrupter of a different phase, such as interrupters 130 and 138, isisolated from the others by an extending barrier formed by the ends ofthe insulating members serving as the tank liner.

Accordingly, through the use of a unitary insulating means formed ofstrips 380, 388, 394 and 396, the tank wall is completely lined, and thedesired insulating barriers are provided whereby communication of gasbubbles from an interrupter to the tank wall or to an adjacentinterrupter is prevented.

Securing the cross bars to the lift rod In the past, a wooden lift rodsuch as wooden lift rod 242 of FIGURES 4, 19 and 20 has been secured toits cross bars 228 and 230 by first forming an accurate notch in thesides of lift rod 242 as shown in FIGURE 19 and then inserting crossbars 228 and 230 in this notch. A first and second bolt, such as bolts400 and 402, rigidly attach cross bars 228 and 230 to the lift rod 242as best shown in FIGURES l9 and 20. Note that FIGURE 19 is across-sectional view of FIGURE 20 taken across the lines 1919 of FIGURE20.

This method of securing is subject to two disadvantages. The first isthat the notch in the wooden lift rod must be very accurately cut, andsecondly, it decreases the strength of the wooden lift rod since itdecreases its crosssectional area for a relatively long axial length.

A further feature of the present invention is to modify the method ofsecuring the lift rod and cross bars in the manner shown in FIGURES 21and 22.

Thus, in FIGURES 21 and 22, the cross bars 228 and 230 are positionedwith respect to lift rod 242 by keys 404, 406, 408 and 410. As best seenin FIGURE 22, from which the cross-sectional view of FIGURE 21 isderived'across lines 2121 of FIGURE 22, the keys such as keys 404 and406 run across the width of lift rod 242. By using these key members, itis only necessary to form keyways in the cross bars 228 and 230 andcooperating keyways in lift rod 242 whereby a greater gripping strengthis provided between the cross bars and lift rod, and a machiningoperation can be done with less accuracy.

16 The securing of the cross bars 228 and 230 is similar to that ofFIGURES l9 and 20 whereby bolts 412 and 414 are placed on either side oflift rod 242 as shown in FIGURE 22.

Securing the movable contact to the cross bars In the past, the movablecontact is connected to a conductive block which is in turn connected tothe cross bars. Thus, as shown in FIGURE 23 for the case of movablecontact 148 and cross bars 228 and 230, the movable contact isthreadably secured to a threaded opening 418 in conductive block 418which may be made of aluminum. A notch is cut on either side of block418 to receive the cross bars 228 and 230 in much the same manner as thewooden lift rod receives these cross bar members in FIGURE 19. Hereagain, an accurate machining operation and substantial decrease instrength of the block is required.

Securing blocks such as bolt 420 are then placed on either side of themovable contact to rigidly clamp members 228, 230, 418 and 148 together.Here again I have found that a novel keyway construction can be used tosimplify the securing of the cross bars to the block.

Thus, as is shown in FIGURE 24, movable contact 148 is threadablysecured to aluminum contact block 244, and the cross bars 228 and 230have keyways therein which cooperate with keyways in block 422 toreceive keys 424, 426, 428 and 430.

As is best seen in FIGURE 25, which is a cross-sectional view of FIGURE24 taken across lines 25-25 of FIGURE 24, the block 422 has a slot 432therein so that upon the tightening of bolts 434 and 436, the slot 432is drawn inwardly to rigidly secure the threaded connection betweenblock 422 and contact 128.

An alternative method of connecting the movable bayonet type contact 148to cross bars 228 and 230 is shown in FIGURES 26 and 27 which stillprovides the key construction using keys 424, 426, 428 and 430 of FIGURE24 to connect the cross bars to block 422. In the case of FIGURE 26,however, block 422 has a threaded insert member 434 of conductivematerial which receives bayonet contact 148 in an off-center threadedopening.

Accordingly, by rotating ring or insert 434, the movable bayonet contact148 will be displaced in a lateral plane with respect to cross bars 228and 230 and achieve adjustment of the position of the bayonet contact148.

As is seen in FIGURE 26, which is a top view of FIG- URE 27, ring 434has a slot 436 therein, while block 422 has a slot 438 therein.Accordingly, as the clamping bolt 440 is tightened, .both slots 430 and438 will be compressed to cause a firm connection between block 422 andring 434 and then ring 434 and contact 148.

Round Fiberglas lift rod and guide means therefor As previouslydescribed in FIGURE 4, the square wooden lift rods 242, 244 and 246require a relatively complex guiding structure.

I have found that a tubular plastic tube which could be made ofFiberglas can be used for the body of the lift rod. Some of the problemswhich exist in the use of the round plastic tube which could be ofFiberglas are in the guiding of the relatively long tube and in themanner of connecting the tube to the steel connecting links such as link302 of FIGURE 4 which is connected to the output of the operatinglinkage at one end and to the wooden lift rod at the other end.

In FIGURE 28, I have shown one manner in which a Fiberglas tube 442 canbe used for the body of the lift rod. In order to secure this Fiberglasrod to steel member 302, I have found that by providing a 2 taper in theinner tube opening of tube 442 and a cooperating 2 taper on the end ofrod 302 and by using a glue joint between these two tapers which couldbe of an epoxy resin that an extremely rigid connection can be formed.The 2 taper is essential, and it has been found that a relatively I 7large variation from this 2 taper defeats the strength of the joint.

In addition, it may be desirable, since the rod 442 is hollow, toprovide an air hole 444 in the metal link 302.

In order to guide this long round rod, I provide a guide tube 446 whichmay be of steel and is concentric with rod 442. The upper portion ofsteel tube 446 is then secured to the frame 248 of FIGURE 4, and thelower end of the tube is provided with an annular guide insert 448 whichmay be of Bakelite. Where the rod 442 has a diameter of roughly 1 /2", Ihave found that the clearance between the rod and the inner diameter ofinsert 448 should be ,4, to achieve the required degree of guidance.

The lower end of the tube 442 which is to be secured to cross bars 228and 230 through the intermediary of a block 450 which may be of aluminumis achieved through the use of a split wire ring 452 which may be ofbrass. More specifically, split wire ring 452 is first contained withina notch in the lower end of rod 442 which has sufficient depth to allowthe wire to fall flush with the outer diameter of rod 442. The innerannular notch 454 is then provided in block 450 which permits ring 452to expand when annular notch 454 is rigid, whereby rod 442 is rigidlysecured to block 450. The block 450 is then connected to cross bars 228and 230 by keys such as keys 424, 426, 428 and 430 shown in FIGURE 24.

Although I have described preferred embodiments of my novel invention,many variations and modifications will now be obvious to those skilledin the art, and I prefer therefore to be limited not by the specificdisclosure herein but only by the appended claim.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

In an oil tank for a three phase oil blast circuit breaker; a first,second, and third interrupter assembly connected to a respective phaseof a three phase line being positioned in spaced relation within saidoil tank; a tank liner combined with interphase barriers; said tankliner and interphase barriers being comprised of a plurality of sheetsof insulating material; said sheets of insulating material defining arespective chamber for each of said first second and third interrupterassemblies; said tank having an interior surface; each of said sheetsintegrally including a portion of said tank liner and extending portionsextending from the interior surface of said tank to an area interposedbetween said interrupter assemblies; each of said sheets being adjacentand between two others of said sheets and each of said sheets definingone of said chambers with adjacent ones of said extending portions ofadjacent sheets defining said barriers.

References Cited UNITED STATES PATENTS 1,634,444 9/1927 Burnham 200-2,028,963 1/1936 Wood 200-450 2,283,874 5/1942 Nye 200-150 3,157,76911/1964 McCloud 200-450 ROBERT S. MACON, Primary Examiner.

